[time-nuts] WWVB BPSK Receiver Project? (fwd)

Marek Peca marek at duch.cz
Sat Mar 17 13:38:05 UTC 2012


> Any filter's group delay can be equalized by all pass filters.
>
> Delay builds up at the filter corner. Since everything in the real world is 
> causal, you add delay outside that corner frequency but in the passband to 
> equalize it. This is to say, you can't remove delay, but just add it to 
> flatten out the group delay.

Yes, the compensation can be made and it has been also pointed out in the 
first comment by Poul-Henning.

The only remaining question is, how stable are the analogue filter 
parameters over time, to be compensated by fixed digital filter. It seems 
to me, that some very small phase errors produced by such a filter-filter 
mismatch may be acceptable.

At least for low-cost device which I would like to rebuild and offer for 
WWVB audience (which is not present in our land).


Best regards,
Marek



More information about the time-nuts mailing list